//
// Created by Administrator on 2023/11/19.
//
#include "iostream"

using namespace std;
const int N = 1e3 + 10;
char A[N], B[N];
int dp[N][N];

int main() {
    int n, m;
    cin >> n >> m;
    for (int i = 1; i <= n; ++i) {
        cin >> A[i];
    }
    for (int i = 1; i <= m; ++i) {
        cin >> B[i];
    }

    for (int i = 1; i <= n; ++i) {
        for (int j = 1; j <= m; ++j) {
            if (A[i] == B[j])
                dp[i][j] = dp[i - 1][j - 1] + 1;
            else
                dp[i][j] = max(dp[i - 1][j], dp[i][j - 1]);
        }
    }
    cout<<dp[n][m];
}